First: Take the MSF BRC, pass the written/riding tests and get the motorcycle endorsement on your drivers license.
Second: Gear up! Get a helmet, jacket, gloves, boots, and eye protection (if you decide against a full-face helmet). Many MSF classes will give you coupons for good discounts on gear. And many cycle shops will give discounts on gear if you show them your MSF BRC course completed card.
Third: Try to find a friend/relative who is an experienced rider. They can be a great help when you are shopping for bikes and when you are practicing your riding skills.
Fourth: Buy a bike.
For your first bike, I'd suggest you buy something used with a lower-powered engine, and don't spend much money. More than likely, you're gonna drop this bike a few times and you don't want to bash up a shiny new bike. Also, when you are ready for a nicer, more powerful bike, you can sell your first bike. Unless you overpaid, you'll likely get most of your money back. Use that as a nice down-payment on your shiny new perfect bike.
Try Craig's List and look for a cheap lower-powered bike to learn on. Remember, this is not going to be your dream bike, or even a bike you expect to keep for a very long time. You should probably ride this bike at least one riding season, and then in the early spring of the next riding season, put it on the market for sale and ride it until it sells. Then you should be in good shape to buy a better longer-term motorcycle.
Try not to get impatient and begin riding a bike without taking the MSF class. You may end up thinking you don't need the class, and I think that is a mistake. The MSF class is excellent and I recommend it even for experienced riders.